The following study showed that the relative degree of involvement of the
different quadriceps muscles depends on knee angle and angle of rotation of
the hip joint. It noted that there is relatively more activation of vastus
medialis obliquus (VMO) than vastus lateralis at 40 degrees of semi-squat
with the hip medially rotated by 30 degrees.
Note that we have always been warned not to allow the hips (actually the
femur) to rotate inwards during any stage of the squat, yet this study
concludes that this so-called contraindicated action actually strengthens
the VMO more effectively. Does this mean that internal rotation of the femur
may offer a useful method of strengthening VMO during normal squats and that
coaches shouldn't become overexcited about athletes doing partial squats with
internally rotated femurs? Are we weakening our athlete's quadriceps or
creating some imbalance in their muscles by avoiding squats which permit some
level of internal hip rotation (note that in this regard we need to dist
inguish between inward tilting of the knees and internal rotation of the
femur).
Incidentally, this type of partial squat has been used in karate training for
many years, so that there appears to be at least one sporting precedent for
its use.
-----------------
Am J Phys Med Rehabil 2001 Nov; 80(11):804-8
Activation of the quadriceps muscle during semisquatting with different hip
and knee positions in patients with anterior knee pain.
Lam PL, Ng GY.
OBJECTIVE: We measured the surface electromyographic activities of vastus
medialis obliquus and vastus lateralis in 16 subjects with patellofemoral
joint pain syndrome.
DESIGN: Each subject performed bilateral static knee extension exercises at
60% of his or her maximal voluntary effort under different combinations of
hip rotation (30 degrees of medial rotation, neutral, 45 degrees of lateral
rotation) and knee flexion (20 and 40 degrees) in a standing position. The
ratio of surface-integrated EMG signals of vastus medialis obliquus over
vastus lateralis was calculated for each of the six conditions. Because of
significant interaction of hip rotation and knee flexion in the two-way
analysis of variance, data were analyzed separately with paired t tests for
the effect of knee positions and one-way repeated measures analysis of
variance for hip positions.
RESULTS: At 20 degrees of knee flexion, there was no significant difference
among the three hip positions, whereas at 40 degrees of knee flexion, medial
rotation of the hip resulted in significantly higher vastus medialis
obliquus over vastus lateralis activity ratio than lateral rotation.
CONCLUSIONS: There was relatively more activation of vastus medialis obliquus
than vastus lateralis at 40 degrees of semi-squat with the hip medially
rotated by 30 degrees. This finding has clinical implications for training
the vastus medialis obliquus in patients with patellofemoral joint pain
syndrome.
-----------
Dr Mel C Siff
Denver, USA
different quadriceps muscles depends on knee angle and angle of rotation of
the hip joint. It noted that there is relatively more activation of vastus
medialis obliquus (VMO) than vastus lateralis at 40 degrees of semi-squat
with the hip medially rotated by 30 degrees.
Note that we have always been warned not to allow the hips (actually the
femur) to rotate inwards during any stage of the squat, yet this study
concludes that this so-called contraindicated action actually strengthens
the VMO more effectively. Does this mean that internal rotation of the femur
may offer a useful method of strengthening VMO during normal squats and that
coaches shouldn't become overexcited about athletes doing partial squats with
internally rotated femurs? Are we weakening our athlete's quadriceps or
creating some imbalance in their muscles by avoiding squats which permit some
level of internal hip rotation (note that in this regard we need to dist
inguish between inward tilting of the knees and internal rotation of the
femur).
Incidentally, this type of partial squat has been used in karate training for
many years, so that there appears to be at least one sporting precedent for
its use.
-----------------
Am J Phys Med Rehabil 2001 Nov; 80(11):804-8
Activation of the quadriceps muscle during semisquatting with different hip
and knee positions in patients with anterior knee pain.
Lam PL, Ng GY.
OBJECTIVE: We measured the surface electromyographic activities of vastus
medialis obliquus and vastus lateralis in 16 subjects with patellofemoral
joint pain syndrome.
DESIGN: Each subject performed bilateral static knee extension exercises at
60% of his or her maximal voluntary effort under different combinations of
hip rotation (30 degrees of medial rotation, neutral, 45 degrees of lateral
rotation) and knee flexion (20 and 40 degrees) in a standing position. The
ratio of surface-integrated EMG signals of vastus medialis obliquus over
vastus lateralis was calculated for each of the six conditions. Because of
significant interaction of hip rotation and knee flexion in the two-way
analysis of variance, data were analyzed separately with paired t tests for
the effect of knee positions and one-way repeated measures analysis of
variance for hip positions.
RESULTS: At 20 degrees of knee flexion, there was no significant difference
among the three hip positions, whereas at 40 degrees of knee flexion, medial
rotation of the hip resulted in significantly higher vastus medialis
obliquus over vastus lateralis activity ratio than lateral rotation.
CONCLUSIONS: There was relatively more activation of vastus medialis obliquus
than vastus lateralis at 40 degrees of semi-squat with the hip medially
rotated by 30 degrees. This finding has clinical implications for training
the vastus medialis obliquus in patients with patellofemoral joint pain
syndrome.
-----------
Dr Mel C Siff
Denver, USA
, sondern sind - wie es dieses paper in der conclusion anführt - klinische implikationen. genauso wie bei einer vorderen kreuzbandruptur die hamstrings gekräftigt werden müssen, kann ich mir vorstellen, dass es auch biomechanischen sinn macht, unter gewissen umständen die vasti gezielt zu kräftigen. da müsste man einmal einen spezialisten für die kniegelenksbiomechanik fragen.